Having Trouble to deploy a Rails App to Heroku - ruby-on-rails

Question

I'm having trouble to deploy a rails app to Heroku. Heroku is giving me the Error Message An error occurred while installing Ruby ruby-2.1.1 which is confusing me after all that I've done to set everything to ruby 2.0.0.
Any Ideas? Thanks!
My Steps so far:
I searched here https://devcenter.heroku.com/articles/ruby-support#supported-runtimes for a ruby version that is currently compatible.
I Installed the Version Ruby 2.0.0 via RVM on my Computer
I made sure that this version is used: rvm use ruby-2.0.0
I added the line ruby '2.0.0' to the App's Gemfile
I did run bundle install (No Error Messages)
I did run git push heroku master
The Heroku Errormessage:
> ~/Desktop/blog(heroku_deploy) git push heroku master
Counting objects: 61, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (49/49), done.
Writing objects: 100% (61/61), 14.77 KiB | 0 bytes/s, done.
Total 61 (delta 26), reused 41 (delta 7)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> Removing .DS_Store files
remote: -----> Ruby app detected
remote: -----> Compiling Ruby/Rails
remote: !
remote: ! An error occurred while installing Ruby ruby-2.1.1
remote: ! For supported Ruby versions see https://devcenter.heroku.com/articles/ruby-support#supported-runtimes
remote: ! Note: Only the most recent version of Ruby 2.1 is supported on Cedar-14
remote: ! Command: 'set -o pipefail; curl --fail --retry 3 --retry-delay 1 --connect-timeout 3 --max-time 30 https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/cedar-14/ruby-2.1.1.tgz -s -o - | tar zxf - ' failed unexpectedly:
remote: !
remote: ! gzip: stdin: unexpected end of file
remote: ! tar: Child returned status 1
remote: ! tar: Error is not recoverable: exiting now
remote: !
remote:
remote: ! Push rejected, failed to compile Ruby app
remote:
remote: Verifying deploy....
remote:
remote: ! Push rejected to quiet-springs-8925.
remote:
To https://git.heroku.com/quiet-springs-8925.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/quiet-springs-8925.git'
The Gemfile:
source 'https://rubygems.org'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
ruby '2.0.0'
gem 'rails', '4.1.5'
gem 'bcrypt', '3.1.7'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.3'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc
# Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem 'spring', group: :development
group :test do
gem 'minitest-reporters', '1.0.5'
gem 'mini_backtrace', '0.1.3'
gem 'guard-minitest', '2.3.1'
end
group :production do
gem 'pg', '0.17.1'
gem 'rails_12factor', '0.0.2'
gem 'puma', '2.11.1'
end
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'
# Use unicorn as the app server
# gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development
# Use debugger
# gem 'debugger', group: [:development, :test]

Answer 1

Heroku doesn't support Ruby 2.1.1. Like it says in the errors, you can find which ruby runtimes work here.
Quick look at the Ruby runtimes that work gives: 1.8.7, 1.9.2, 1.9.3, 2.0.0, 2.1.6, 2.2.2.